Gear wheel and method of manufacturing the same



Patented lvlay d, llld narran stares carica,

' JEI ECKERT, C@ MELWAUKEE, WSCGNSIN.

@MR WEEL MTD METHOD F MANUFACTURXNG THE .application filed i'ay 24:,

gear wheels and methods of manufacturing the same, and pertains especially to gear wheels having teeth projectmg laterally from the normal plane thereof, such, for example, as hevel gear wheels and crownl ywheels.

'lhe object of this invention is to expedite the manufactured bevel and crown gear wheels hy hammer forging them from blocks or plates of rolled steel'in such a manner as to completely contour the working faces of the teeth during the hammering operation. Also to provide gear wheels or en ceptional strength, the surfaces oi? the teeth heing densied or hardened by hammering during the forging operation without scraping or otherwise roughening the surfaces during such operation. l have discovered that it is possible by this process to not only form hevel gear wheels and crown wheels with great rapidity in a. single set el hamn mer forges, hut that such wheels may be so 'ormed as to he substantially perfect vin contour. By thepresent process, the drawhache to rolled gear manufacturaparticularly that due to the wave motion, that is to say, the wave that is produced in the rolling blank in advance of the point of con- 'tact of the rolling shaping tool, and the scraping motion due to the withdrawal of the teeth of the shaping tool from the revolving blank,are avoided. Also, the drawbacks to the :forming of gears by a pressing operatiom such as that secured by the use ora a hydraulic press,particularly v that of sticking and subsequently cooling in the press,are avoided. ln a hydraulic press, for. instance, the teeth of the gears which are located between the teeth of the die cool down and tend to grip the teeth of` the forming die, even tho the teeth of the forming die .maybe coatedwith graphite.

.By the resent process thetemperature of the hlan ismaintained by the continual 1nluws oi the hammer and alsorall of -the arts of the gear are simultaneously sub# geoted to the same sudden impulses or blows,

192e. serial' ne. seance.

thereby preventing Wave motion and uneven stresses; and also preventing'sticliing by the jarring action of the blows.

ln general, my process may as follows Pieces of metal ot a generally rectanlar forni and ot the required mass are cut from sheets or bars of rolled steel, each piece loeing provided with a projection or tong hold t5 extending from onecorner or side to facilitate manipulation by means or tongs, such as are commonly used for manipulating work in a forging shop or plant.

rlhese pieces of metal are heated to al@ working temperature, and then by means of. the tongs they are successively placed upon a stationary die or anvil, and hammered into shape by a reciprocating plunger, the working contour of which is a counterpart ol the face portion or" the gear wheel to be formed. ln other words, the lower end ol the plun er or hammer constitutes a 'patternto which the working tace of the gear wheel is to be conformed. The central portion of the @0 plunger or hammer projects belowthe concentric portion which carries the hammer teeth, and this central portion is brought into increasingly close proximity` to the opposing surface ot the anvil as the plunger is reciprocated, thereby forcing the metal to flow radially intothe portion of the blank on which the teeth are being formed. Therefore, when the heated metal is placed upon the relatively stationary die and the plunger reciprocated into andout of contact with the blank, the latter will be quickly hammered into shape and teeth ot the del sired contour formedv on its upper surface.

be described eo The remainder of the blank will in, the

meantime assume the form of a wheel having a comparatively thin central web and an outer marginal portion concentric with the annular row of teeth..

press having a die provided with a centrally disposed circular cavity and the central portion is driven out by a cylindrical punch. leavinglr a marginal web within the annular The Wheel is then placed in a punching 109 row ot gearv teeth to be utilized in mounting the gear wheel upon a shaft flange or other appropriate support. .lts outer margin is then trimmed of? in another press, and it is then dipped in, water and the scale removed by a wire brush.

`The cleaned wheelv is then inverted, and placed upon the relatively stationary nishing die or anvil of another hammer forge,

Y this anvil die having pattern teeth between I a turning lathe or otherwise machined. No

finishing work is required for the surfaces of the gear teethn' The working faces of the teeth will be found to be perfectly conformed to the pattern.

Before iinishing, thegear wheels are annealed and normalized to relieve them of internal strains. rlhey are subsequently heat treated to harden them and develop the desired tem er.

The h anhs are ,preferably made large enough to enable them to he hammered into gear wheels of a diameter in excess of the nished gear wheels for the reason that the marginal portion of the stock at the outer ends of the' teeth are thickened, and these thickened portions are out away in the machining operation, thus enabling me to nish the peripheral margin of the wheel -and simultaneously contour the same as required.

My imoroved method and its product will now he rther (-anplainedvvith reference to the accompanying drawings, in which,-

Fig. i is a central vertical sectional view of the working parts of a contouring hammer forge with a spreader'in position on the anvil as it appears during the initial ste of hammering the metal into a circular w eel having a thickened annular portion upon which an annular row of upset hy the hammer.

llig. 2 is a half-section of the same with the spreader removed and the hlanlr'ready for removal after the second hammering operation following the removal of the spreader. i

liie. 3 4is a vertical sectional view" of apunci as it appears uring the operationV of removing the centra portion or web of the gear wheel. f

Fig. 4 is a sectional view of the wheel after the center h'as been removedand therenterior trimmed.

Fig. 5 is a view-'of the blank in` position in the nishing hammer forge, this forge and the wheel heing illustrated in centralverti cal section. y f

El 6 is a fragmentary view of the gear gear teeth is being interes Fig. 8 is a fragmentary cross section of one of the 'teethand a portion of the hack also showing the grain lines.

A. block or piece of rolled steel l, having a tong hold 2, 'is heated in a furnace to a forging temperature, and then placed upon a circular spreader 3 loosely mounted upon theanvil 4 of a Contouring hammer forge.

l provide the hammer 6 'of the forge with ay working surface which conforms generally in shape to the toothed face of the gear wheel to be formed. For convenience, it will he referred to as the hammer die. It has an annular portion 7, whichfif a beveled gear wheel is to be produced, will he inclined at the proper pitch and radially grooved to serve as a pattern for the teeth of the gear wheel to be formed. The central portion 8 is in the form of a disk and is in such a' relation to' the toothed portion that when the hammer is brought into Contact with the heated work, the latter will be driven outwardly and caused to flow into the portion from which the teethare formed, the latter being thickened and also upset and conformed to the contour of the portion 7." The y outward or radial flow of the metal isconsiderable during the initial;hammeringoperation, due to the fact that the central portion of the spreader is drivenpupw'ardly into the metal from the under side. Afterl a few blows ofthe hammer the spreader isvremoved and the hammering operation continued until the. teeth are upset to substantially their full height, the central portion of the 'web being in the meantime driven downwardly upon the portion 9 of the anvil. rlhis pori tion 9 of the anvil is slightly raised above the surrounding portion 10 which receives the thicker portion ofthe wheel, and is en circled by a raised portion 11- which limits the outward flow ofthe metal.

The wheel thus formed in the contourin hammering forge is then removed from sucl forge and thecentral portion removed hyla punch 12, the die of which has a .circu-v lar aperture of the `required diameter. `rlhe 'ragged outer margin is then similarly .-timmed off hy a cylindrical punch (not shown), after. whicht the resulting ,toothed ring is dipped in water and the scale removed hy a wire hrush. v l The wheel is then inverted and. placed upon the anvil die l5 of a finishing hammer v forge having a radially grooved annular portion 16 which has been perfectly contoured to serve as a pattern for the gear teeth. lhe' upset teeth of the wheel enter the groovesofthe pattern, and the hammer l7 of this forge is reciprocated upon the hack` side of the wheel to force the latter into substanwhee as delivered from the finishing forge.

Fig. 7 is a sectional view showing a fragment orf the completed wheel and indicating the tially perfect conformity with the pattern. This anvil or pattern die 15 has an outer circular marginal portion 19 of somewhat greater diameter than the'gear. wheel when lill) smooth,I and perfectly conformed to-the pitt` radial, from the central` portion outwardly,

all but the extreme vouter portions` of the teeth may be fully conformed to the pattern die with a few strokes of the hammer.

The-reversal ofthe Wheel in the finishing hammer forge, and the fact that the hammer is applied to the rear face in this forge, is

also an important feature of my process. By'

using a perfect contouring anvil, perfect teeth may thus be formed, and distortion of the pattern is much less apt to voccur than in the initial contouring hammer forge. But

in the initial or contouring hammer forge it' is very important to employ a patterned hammer, as the teeth are thereby readily upf set by the impacts of such a hammer upon the heated metal.

i icfter the wheel has been contoured in the finishing hammer forge it is allowed to cool, and is subsequently heat treated to harden and temper it. lt is also trimmed or finished by cutting or grinding away the surplus Inaterial, andfaced ofi along the inner .and outer margins. As above stated, the teeth require no finishing operation, being wholly contoured in the hammer forges. ln fact, it

is not desirable to cut them as their `hammered surfaces are not only perfect, but

strengthened by the hammered process and the grain lines of the metal extend from the back or body into and out of the teeth along curved lines, as illustrated.

It will of course be understood that the anvils and hammers, as well as the Work may be cleaned by a blast of steam or air While in operation, in accordance with vvell known forging practice. v

y By hammering the metal into the desired shape, the succession of quick impacts makes it possible to readily conform the metal; maintain its ytemperature during the entire operation; avoid adhesion, wave motion, and uneven strains, and also the necessity of employing as heavy rpressure as would otherwise be required.

of the'teeth, and it is my belief that it produces better and stronger teeth than can be produced by presses in which impacts are avoided. "The teeth require no finishing Whatever, their bearing surfaces being very-hard,

tern, and the grain 'of they, metal being continuous from the body into and out of the teeth along curved lines,v whereby teeth of great strength and" durability are'produced.

he hammering process. also facilitates securing perfect conformity Improved beveled gear wheels made in accordance with my process are peculiarly breaking of gear teeth has heretofore caused much annoyance and expense.-

- I claim: u l l 1. The method of forming gear wheels having laterally projecting teeth, consisting -in heating blocks of metal, hammering them with a pattern die having an annular row of grooves into which the teeth may be upset, inverting the wheel thus formed and placing the same in a similarly contoured relatively stationary pattern die and hammering the other face of the wheel to force he teeth into final conformity withv such 2. The method of forming gear Wheels having laterally projecting teeth, consisting in heating blocks of metal, hammering them with a pattern die having an annular row of grooves into which the teeth may be upset, inverting the Wheel thus formed and placing the same in a similarly contoured relatively stationary pattern die, hammering the other face of the wheel to force the teeth into final conformity with such die,`

placing its toothed portion in a similar pattern die and'hammering tliefopposite side thereof to force the upset teeth into more perfect conformity with the grooves `in suoli pattern die, and then removing, trimming and heat treating the resulting product.

4:."l`he method of forming gear wheels having laterally projecting teeth, consisting in placing blocks of heated metal upon an anvil having a circular recess, hammering said metal with a circular pattern die provided with anannular row of radially extending grooves inwvhich the metal is upset to form teeth and simultaneously hammering the central portion of the metal to cause the saine to How radially into said upsetting portions, removing the scale from the wheel thus formed, punching out the central port/ion, placing the Wheel .in an anvil die having grooves to receive said teeth, forcing the' metal into conformity with such walls, and subsequently trimming the margins. of the wheel and heat .treating and tempering the same. i

5. The method of. forming gear Wheels, consisting in heating a block of metal, forcing it to assume an annular shape and upsetting an annular row of teeth thereon to form a wheel'having the general Contour said finishing die by a succession of blows.

6. A gear wheel having upset teeth provided with directly hammered faces and having a rear hammered surface.

7. The method of forming gear Wheels comprising. heating blanks of metal and hammering them into conformity with a pattern having grooves accurately contoured to the Working faces of the teeth of the il) desired gear Wheel.

8. rlhe method of forming gear Wheels comprising forming metal into the 'general contour or" a gear Wheel, placing the same in a pattern die having grooves accurately contoured in conformity with the Working faces of the desired gear. teeth, and lsubjecting the metal to a succession of rapid impacts to simultaneously force all of the teeth into conformity with lall of the grooves in the pattern die.

9. A `fear Wheel having teeth provided With hammered Working faces.i said faces being inished hy final hammering.

ln testimony whereof l affix my signature in the presence of two Witnesses.

Jona nonnen l/Vitnessesy:

A. J. MCKERIHAN C. ifi/"nenn 

